The invention relates generally to a depository safe or the like type of security boxes with closure doors having combination type locks thereon which include slots or apertures generally on the face thereof for receiving money, jewelry and the like type of valuables for safe keeping in the depository safe box without the requirement of opening the closure or access door thereof. More particularly the present invention relates to a shutter assembly for normally maintaining said slot or aperture on said depository safe or security box closed and blocked from entry but adapted to be operated for opening the slot or aperture preferably by means of a lock and key operated actuator.
Although a number of shutter assemblies for slots or openings are known in the prior art as is shown in U.S. Pat. Nos. 2,967,015; 1,852,053, and 1,607,361, it has been found that such closure members are unduly complicated and have only limited usefulness as for those special applications for which they are constructed.
Some prior art devices require that a sizable force has to be imparted to the actuator, generally a key in order to open the slot, aperture or door for transfer of the valuables to be deposited in the depository safe or security box.
Further, certain shutter assemblies for the slots or apertures on said deposit or security boxes require certain geometric configurations or shapes to obtain that particular type of operation. Such shutters are very elaborate and require complex mechanisms which are expensive to make. Therefore, when such devices are utilized it is often difficult to provide the desired strength for the walls of the devices without the considerable expenditure required to machine these complicated structures from the very heavy materials desirable for such purposes.
It is thought fundamental that where slots or apertures are provided the closure assemblies therefor must of necessity be very strong to prevent unauthorized and unlawful access to the valuables or other materials deposited in the depository safe or security box. Further not only must they have strength but in addition they must be so constructed that the "fishing" of items from the depository safe or security box is prevented.
The present invention provides a simple shutter mechanism or closure assembly which is strong and durable in construction, normally disposed to maintain a slot or aperture for the safe deposit or security box closed, which can be safely secured with a lock adaptable and accessible by key means from the exterior of the depository safe or security box, and which shutter assembly is designed to provide a cam mechanism wherein the initial closing torque is so balanced that the forces required for moving the shutter assembly from its open to its closed position are substantially reduced.